Indoor positioning systems exploiting WLAN signal measurements such as Received Signal Strength (RSS) are gaining popularity due to high accuracy of the results. Sets of RSS and other measurements at designated locations from available WLAN access points (APs) are conventionally called fingerprints and retrieved from network cards at typically one Hz rate. Such measurement collection is needed for offline radio-map surveying stage which assigns fingerprints to locations, and for online navigation stage, when collected measurements are associated with the radio-map for positioning. As WLAN network is not originally designed for localization, the network cards occasionally miss the fingerprints, measurement fluctuations necessitate statistical signal processing, and surveying process is very time consuming. This paper describes a fast measurement collection approach that addresses the mentioned problems: higher probability of measurement acquisition, more data for statistical processing and faster surveying. The approach is further analyzed for practical setting applications.